What prevents DIY speakers to become the ultimate?

I spent about $1400 on a pair of DIY speakers, and am extremely pleased with the outcome. I built a set of Voigt Pipe cabinets from oak, and loaded in a set of Lowther EX3 single drivers. The sound is exactly what I was looking for, and the job was quite easy. Didn't have to worry about building a crossover, because I didn't need or want a crossover in my speaker system. Just one, fullrange driver per channel, with point source radiation. No problems, very happy, saved money.

In my experience (twentysomething years of amateur speaker building), crossover design is what primarily separates the men from the boys. Other significant factors can include custom-tailored drivers and exotic cabinet materials.

Note that in my twentysomething amateur years I've amassed perhaps as much experience as a professional does in his first year or so. And I don't have the engineering background that a professional does.

The main practical advantage of DIY is that there are no layers of price markup, and the labor is free (or nearly so). This means that DIY speakers can include a lot of painstaking detail work (especially on the cabinet) that would be prohibitively expensive for a manufacturer.

For me, the appeal of DIY is the joy of creating something that no one else has ever created before. I'm tweaking a high efficiency monster in my living room right now. Yup, it's R&D for a (hopefully) commercial product, but it's also a lot of fun. Assuming my prototypes validate the concepts I'm exploring, I'll engage a professional designer before going commercial.

So, can a DIY design be the ultimate? In 1998, a first-generation commercial effort by longtime amateur designer Siegfried Linkwitz walked away with Stereophile's "Speaker of the Year" award. The Audio Artistry Beethoven was essentially a commercial incarnation of a DIY design, and in fact you can go to Siegfried's website and learn how to build your own Beethoven equivalant, called the Phoenix. I would suggest that amateur speaker builders in the same league as Siegfried Linkwitz have a shot at designing and building a truly "ultimate" loudspeaker. The rest of us are somewhere farther back on the learning curve.

Some folks prefer the Scan-speaks design, Northcreek. Like Njoy, I prefer the Seas Excel design, Thor, an MTM. Thor at under $2K! audiokenesis summed the difference quite well DIY vs commercial. Linkwitz has finally answered the big commercials with his Orion, an open baffel, dual Peerless XLS + Excel W22 (crossed at 1500hz to the tweet) + Excel tweet. The only problem here is that you need to use a ss multichannel amp. Its active xover. So if you love tube amps, won't go. But you can use a tube pre with these. There is not a commercial alive that can touch them, well maybe the big Burmesters at $50K! So as I see it DIYer kits are the ultimate. Now can anyone predict if the commercial market share will take a small hit or big hit from Northcreek or Seas, and will this be soon or much later??? I doubt if anyone wants to take a stab, but something to think about for sure.